Voice Coil Review: Outboard DSP: Marani Pro MIR480I Audio System Processor
March 13 2025, 16:55
In his exploration of available Outboard DSP systems, Vance Dickason explores the Marani Pro Audio MIR4801, the company's flagship DSP processor with four inputs and eight outputs. MIR stands for Marani Impulse Response, which refers to the proprietary Marani linear (zero) phase Linkwitz-Riley filter, which is described in a whitepaper titled by Michael Marani and Simone Castrucci, both from SEED Electronics, Guangzhou, China.
The second outboard DSP unit to be examined in this series of currently available outboard DSP processors is from Italian-based Marani Pro Audio, and is the Marani Pro Audio’s flagship DSP processor, the four in/eight out Marani Pro MIR480I (Photo 1 and Photo 2). MIR stands for Marani Impulse Response, which refers to the proprietary Marani linear (zero) phase Linkwitz-Riley filter, which is described in a whitepaper available online on the Marani Pro Audio website. The paper is titled “MIR a New Technology for Crossover Filters” by Michael Marani and Simone Castrucci, both from SEED Electronics, Guangzhou, China.
Photo 1: Here is the front view of the Marani Pro Audio’s flagship DSP processor, the Marani Pro MIR480I.
Photo 2: The Marani Pro MIR480I is a four in/eight out unit.
As the name Marani Pro Audio implies, Marani is focused on the pro audio side of the DSP market and makes an entire line of pro audio DSP processors, for a total of 13 models in the Marani FI, A, D, E, and P series DSP processors. While their main application is live sound, Marani processors are equally suited for studio and home audio applications. For the purposes of this article, I will be examining just two models in this extensive lineup, the subject of this article, the four in/eight out Marani MIR480I, and in a future issue of Voice Coil, the Marani MIR260A two in/six out DSP processor. Besides the Marani line of pro audio-oriented DSP processors, the company also produces rack mixers, matrix mixers, equalizers, power amplifiers, and feedback eliminators. It’s also interesting to note that Marani Pro Audio has partnered with the Danish Class-D pro audio power amplifier company, Pascal and provides DSP processing boards for Pascal plate amps.
The feature set for the four in/eight out Marani 480I, depicted in Photos 3-5, is extensive:
DSP and AD/DA run at a 96kHz sampling rate.
Functions include input gain, noise gate, PEQ (parametric EQ), compression, delay, polarity, crossover filters selection, peak limiter, auto and dynamic equalization.
A network interface is configured to connect to a PC directly through a network cable. By default, DHCP automatically obtains an IP address. Computer software can control up to 128 processors at the same time via network connections, and can perform unified gain control, mute, PEQ and polarity via any of the control interfaces (USB, RS485/ETHERNET).
FIR Filters—each output can have up to a 512 tap FIR filter for total of a possible 4096 taps with a slope range of 21dB/octave to 120 dB/octave
IIR Filters—Linkwitz-Riley/Butterworth slope: 12/24/36/48dB per octave NXF (notch filter) slope is 40/45/50/50/55/60/65/70/75dB per octave; Bessel 12/24dB per octave.
MIR Filters—Linkwitz-Riley slope: 12/24/36/48dB per octave NXF slope: 40/45/50/50/55/60/65/70/75dB per octave type; high-pass/low-pass/bandpass/external import.
Taps range: 256 ~ 512.
Photo 3: The feature set for the Marani MIR480I is extensive with four inputs.
Photo 4: The Marani MIR480I also offers eight outputs.
Photo 5: This is the inner workings of the Marani MIR480I.
Critical specifications for the MIR 480I are:
A/D dynamic range: 123dB
D/A dynamic range: 129dB
Maximum input level: +22dBu
Maximum output level: +21.5dBu
Total harmonic distortion: <0.0015% (+21dBu 1kHz)
Frequency response: 20Hz~45kHz
Crosstalk: ≦-98dB
Signal-to-noise ratio: ≧116dB +20dBu 1kHz
Noise floor: ≦-96dB (A-weighting)
Common Mode Rejection Ratio: 65dB
It is also important to note that all Marani Pro DSP processors are supplied with a fairly straightforward PC control software that can configure all of the unit’s functions and is compatible with Windows 7-11. As you can see from Photo 3 and Photo 4, you can also configure the MIR480I from the controls on the front panel.
The MIR480I, like all of the outboard DSP units in this series of explications, were measured on an Audio Precision flagship AP555B analyzer courtesy of my friends at Audio Precision, with a special thank you to AP engineer Charlene Chow who performed the measurement sequences for this article. Photo 6 and Photo 7 shows the basic setup for the series of tests for the series of tests that were run on the Marani 480I. Test categories that were performed included total harmonic distortion plus Noise (THD+N), signal-to-noise ratio (SNR), frequency response at 0dB, crosstalk, and last, intermodulation distortion (IMD). Starting with THD+N shown in Figure 1, at 1kHz the number for channel 1 is 95.032dB, and although not shown, the numbers were 95.594 at 10kHz. Figure 2 depicts the SNR graph, which resulted in 116.947dB for channel 1.
Photo 6: This is the setup for the first series of tests that Audio Precision engineer Charlene Chow ran on the Marani 480I.
Photo 7: Here is the setup for the second series of tests.
Figure 1: Graph of the APx555 THD+N measurement for the Marani MIR480I.
Figure 2: Graph of the APx555 signal-to-noise ratio (SNR) measurement for the Marani MIR480I.
Frequency response the Marani MIR480I shown in Figure 3 indicates the unit is absolutely flat from 20Hz to 20kHz, and 1dB down at 36kHz. This test level was set to reference the result to 0dB. The crosstalk graph in Figure 4, shows channel-to-channel isolation averaged about -96dB across the bandwidth.
Figure 3: This is the frequency response graph for the Marani MIR480I DSP processor.
Figure 4: This is the graph of two-channel crosstalk for the Marani MIR480I DSP processor.
The last test (IMD), illustrated in Figure 5, compares the IMD response of the Marani MIR480I with the background IMD of the AP555B.
Figure 5: APx555 IMD graph comparing the Marani MIR480I IMD to the background IMD of the APx555 analyzer.
Taken all together, the MIR480I, like the Danville Signal dspNexus, exhibited very good performance when measured with the AP555B. This unit has a very nice feature set that will be at home in virtually any audio environment, and Marani is purportedly open to manufacturing OEM versions of their processors, or at least custom-branded faceplates. Like the Danville Signal dspNexus, outboard DSP units such as the Marani MIR480I will likely begin to decrease the home audio’s preference for passive filter designs a trend that certainly will make amplifier manufacturers happy supplying one amp per transducer in a system design rather than just one. For more information, visit the Marani Pro Audio website at www.marani-proaudio.com. VC
This article was originally published in Voice Coil, September 2024
About Vance Dickason
Vance Dickason has been working as a professional in the loudspeaker industry since 1974. A contributing editor to Speaker Builder magazine (now audioXpress) since 1986, in November 1987 he became editor of Voice Coil, the monthly Periodical for the Loudspeake... Read more
